Please help... having issues with my comp

[Entropy1982]

So my northbridge chipset fan broke so i had to replace it... the company sent me a new one and i replaced it (had to fight w the mobo and stuff a bit in the process cuz i didn't want to unplug anthing). plugged everything in finally and turned on the comp... all the fans worked fine computer started but then it didnt detect a single hard drive (none of my 3 SATA drives) but it did detect my dvd drive (ide).... what could i possibly have unplugged?